I remember seeing this car at the national motor museum when i was a kid. We were there on a school trip and all the boys were very impressed at the wild features.
I found some info about the project from;
http://www.sigmaturbo.com/sigmaturbo_048.htm

"It serves as a timely reminder of how big turbocharging was in the late '70s and early '80s and how Chrysler Australia looked at it as a potential saviour, before the company surrendered to a takeover by Mitsubishi in 1980.

According to documentation supplied by the museum, the "Sigma Turbo" show car pictured here was a highlight of the 1980 Melbourne Motor Show. Apparently this one-off wild-bodied Sigma sedan was the brainchild of Chrysler National Sales Promotion Manager, Malcolm Miller, to try and re-stimulate interest in the 2.0 litre Sigma range following the introduction of the larger 2.6 litre Astron engine.

To do that, the Chrysler factory had been experimenting with various turbocharged versions of its locally-made Astron 2.0 litre four cylinder engine and needed a show car that could get the public all excited about the program's potential. The wild body treatment was farmed out to Alan Pervis, who was building the VW-based Pervis Eureka sports car at the time and had the necessary expertise in fibreglass construction techniques.

Pervis based his Sigma design on the wild-looking European Group 4 racing sedans of the era, like works Porsches and BMWs. His fully enveloping aero bodywork included a huge front spoiler, boxed wheel arch flares, side skirts, large integrated rear wing and various scoops and vents. Fat wheels, big rubber and Recaro seats filled in the gaps."

I forgot to get shots of interior, it was clad in orange and red velour!

Some original magazine scans from the time;

I might offer my boss $50 for the scrap!
Just kidding! I would love to get it running.

_________________Too many Mazda's in the collection. 4 Mitsubishi's, 6 Toyota's and now 3 Datsun's as well.
Putting together a Mazda/Japanese motor museum. New bigger venue for the museum has been bought, watch this space!

i have heard some people say that it dose not have the turbo engine. Perhaps the engine specs were "virtual" specs, or someone swapped out/over the motor years ago.
Think im down there tomorrow, will try and take a peek and get some shots under the hood.

Why was this ever taken from Birdwood Motor Museum???? I also remember always loving this car since I was a kid and I took a photo of it every single time I went to visit the Museum. The last time I was there which was earlier this year for Rock 'N' Roll Rendezvous, I went looking for this car and was disappointed because I couldn't find it. Now I see why. It looks so sad

Mate, such a shame really, such a rare car sitting like that, particularly after being at the museum, it would be welcome anytime at my museum shed! I would like to add a Sigma and that's the coolest around!

_________________Too many Mazda's in the collection. 4 Mitsubishi's, 6 Toyota's and now 3 Datsun's as well.
Putting together a Mazda/Japanese motor museum. New bigger venue for the museum has been bought, watch this space!